Trimable headrail insert



FIG. 1 is a perspective view closest to the insertable end of the trimable headrail insert;

FIG. 2 is a front view;

FIG. 3 is rear view illustrating of the trimable end;

FIG. 4 is a right side view, the left side view being a mirror image of the right side view;

FIG. 5 is a top view; and,

FIG. 6 is a bottom view. 

The ornamental design for a trimable headrail insert, as shown and described. 